1. Field of the Invention
The present invention relates to novel cephalosporins and to a process for the preparation thereof. More particularly, it relates to novel cephalosporins of formula (I): ##STR4## wherein X is as described hereinafter, the non-toxic pharmaceutically acceptable salts thereof and to the preparation thereof.
2. Description of the Prior Art
It is known that cephalosporin series compounds such as Cephalothin and Cefazolin are very effective and are widely used as chemotherapeutic agents for infectious diseases caused by gram-positive or gram-negative bacteria.
However, these cephalosporin series compounds have no effect on infectious diseases caused by Pseudomonas aeruginosa which have been increasingly spreading in recent years, and are often very difficult to cure. Cephalosporin series compounds which are effective against Pseudomonas aeruginosa are not yet commercially available.
In Japanese patent application (OPI) No. 35,392/1974, Belgian Pat. No. 808,906, Japanese patent application (OPI) No. 70,990/1974 and in Japanese patent application (OPI) Nos. 87,694/1974, and 82,687/1974, some cephalosporins are disclosed with antibacterial activity against gram-positive and gram-negative bacteria, including Pseudomonas.